Neutron Star Burps Up Stellar Gas

byTammy PlotneronJune 29, 2011

This animated sequence of images illustrates the partial ingestion of a clump of matter by the neutron star hosted in the Supergiant Fast X-Ray Transient, IGR J18410-0535. The ingestion of the clump material produced a dramatic increase in the X-rays released by the neutron star, which was detected with XMM-Newton. The peak in the X-ray luminosity corresponds to the period when the accretion rate was at its maximum. Credits: ESA/AOES Medialab

During a routine twelve and a half hour observation of star system IGR J18410-0535, the XMM-Newton caught an event that would make Emily Post proud… a not-so-discreet burp from a neutron star.

Although it would be ten days before the event was discovered, the ESA XMM-Newton space observatory team observed a faint star flare to almost 10 000 times its normal brightness. By utilizing x-ray wavelengths, the astronomers surmised the surge may have been the product of a neutron star ingesting a giant clump of matter… leftovers from its blue supergiant companion.

“This was a huge bullet of gas that the star shot out, and it hit the neutron star allowing us to see it,” says Enrico Bozzo, ISDC Data Centre for Astrophysics, University of Geneva, Switzerland, and team leader of this research.

The x-ray data revealed four hours of gases being superheated to millions of degrees while being pulled into the gravitational field. Like a thick milkshake being sucked through a narrow straw, very little actually made it to the gravitationally hungry mouth of the neutron star. But had it not been in the way, the material would have simply disappeared into space. It was sheer coincidence the team was looking in the right place at the right time to catch the action from beginning to end.

“I don’t know if there is any way to measure luck, but we were extremely lucky,” says Dr Bozzo. He estimates that an x-ray flare of this magnitude can be expected a few times a year at the most for this particular star system.

From the data, the team was able to extrapolate the size of this “stellar burp” – about 100 billion times the volume of the Moon. From these estimates, astronomers can better understand the table manners of blue supergiant stars and how they transmit their matter into space as stellar wind. This new finding “shows that this particular blue supergiant does it in a clumpy fashion” and by knowing the size and mass allows for reserves to be placed on the process.

Tammy is a professional astronomy author, President Emeritus of Warren Rupp Observatory and retired Astronomical League Executive Secretary. She’s received a vast number of astronomy achievement and observing awards, including the Great Lakes Astronomy Achievement Award, RG Wright Service Award and the first woman astronomer to achieve Comet Hunter's Gold Status.